Preheat the oven for the potato cake (electric oven: 200 °C/circulating air: 180 °C/gas: see manufacturer). Line the bottom of a springform pan (20 cm Ø) with baking paper. Peel and wash the potatoes and cut them into slices of approx. 1⁄2 cm thickness. Puree ricotta and eggs. Season with salt, pepper and nutmeg. Crumble the cheese. Layer potatoes, ricotta cream and cheese alternately in the mould. Finish with ricotta and cheese. Wrap the bottom with aluminium foil. Bake in a hot oven for about 1 hour.
For the salad, mix vinegar, mustard, salt, pepper, sugar and 3 tablespoons of oil. Clean and wash the radicchio and spring onions. Cut radicchio into strips, spring onions into rings. Wash apple, quarter, core and dice. Mix apple and vinaigrette.
For the roast beef, pat the meat dry and season with salt and pepper. Heat 1 tablespoon of oil in a frying pan. Brown the meat thoroughly all around. Reduce oven temperature (electric cooker: 140 °C/circulating air: 120 °C/gas: see manufacturer). Take out the cake and put it aside. Place the meat on the grill on the middle shelf, slide the fat pan underneath. Cook meat for approx. 30 minutes. Switch off the oven. Put the cake back in to warm it up.
Peel and wash the carrots and cut them in half lengthwise. Heat butter and approx. 5 tbsp. water. Steam carrots for 8-10 minutes. Season with salt, pepper and sugar. Mix prepared salad ingredients into the apple vinaigrette. Cut meat into slices and cake into pieces. Serve with salad and carrots.